These features are limited to a specific demographic (those who are 18+ and live in the US) and are 'eligible' (whatever that means) though.
Google certainly has to walk a fine line here because it's not like the hardware they are selling is compelling by itself.
True. Being "stock" (free of unremovable spyware/crapware) and getting OS updates are the primary benefits of Pixel devices for me.
I'm on a Pixel right now as well and, just like you say, it's the software experience that sells it. Enough to justify my next phone also being a Pixel? Jury is still out on that.